Meniscus Surface Research Articles

A reinvestigation on combined dry and wet adhesive contact considering surface tension

The present study theoretically explores combined dry and wet adhesive contact between a rigid sphere and elastic semi-half substrate, in which dry contact is encircled by liquid bridge. We consider threefold effects of liquid bridge on contact behavior, namely Laplace pressure induced by the curved surface of liquid meniscus, surface tension at the triple-phase junction and alternation of adhesion energy between solid surfaces ascribed to liquid immersion. A clear novelty in this study is the investigation on the effect of surface tension at the vapor-liquid-solid junction on the adhesive contact response, in contrast to previous studies. The model solution predicts that the contact behavior and adhesive strength are strongly dependent on surface wettability (manifested by contact angle), liquid volume and the contact system's rapidity in achieving thermodynamic equilibrium. It is found that the transition of the pull-off force is evidently different from Maugis-Dugdale model in terms of a couple of interesting characteristics. Moreover, it is unveiled that the jump instabilities and hysteresis of force-separation curves are highly affected by surface wettability and liquid volume. These theoretical results can not only shed lights on the mechanism of liquid-mediated adhesion employed by animals and plants, but also provide us inspiration for development of biomimetic adhesive devices.

Mechanically forced meniscus water waves in a square container with functionalized wetting conditions

Capillary–gravity surface waves, called meniscus waves, are excited at the air–water interface near the lateral boundary of a mechanically forced square container. Experiments are conducted in two working containers: one is overall hydrophilic at four boundaries and the other is functionalized to have a hydrophobic boundary. The static meniscus structures and instantaneous wave topography are reconstructed at high resolution from the side-view and top-view high-speed camera recordings. Wave resonances arise from the interaction of four inward-traveling waves, with the frequency-response characteristics indicating the effect of wetting conditions on the selection of standing wave patterns. The most-resonant modes are identified as a superposition of dominant modes and higher-order components. An analytical model of the rest-state meniscus and resonant-state wave surface decomposes the wave responses into two groups of resonances along two transverse directions linked by a frequency-dependent parameter γ. Theoretical selection of the dominant wave components and the second-order harmonics is in close agreement with the spatiotemporal surface-fitting experimental results. Additionally, the wetting boundary conditions can be functionalized to excite specific standing wave patterns, which could provide a novel approach to precise pattern control in bioprinting technology for tissue engineering applications.

MR imaging methods to study meniscal position and mechanics

ObjectiveMeniscal mechanics have been studied widely due to the high prevalence of meniscal injuries and their strong association with knee degeneration. Computational models and cadaver studies have contributed to our understanding of the menisci but require assumptions to extrapolate to living people. Imaging modalities provide the ability to make key measurements in vivo. In particular, magnetic resonance imaging (MRI) provides the three-dimensional (3D) visualization of the menisci required to make important measurements related to mechanical function. This mini review summarizes MR approaches that have been used to make measurements related to meniscal mechanics, including morphology, position, movement, shape, and extrusion. DesignA literature search was performed using PubMed and Google Scholar, with search terms including “meniscus” and “MRI” in combination with “mechanics”, “position”, “shape”, “movement”, “size”, “loaded”, and “unloaded”. Articles were manually reviewed and selected by consensus between the authors as constituting the most important examples of work required to illustrate the breadth of measurement and imaging approaches used in research on meniscal function. ResultsMRI has been used for quantitative 3D analyses of the morphology and position of the menisci. Morphological analyses included measurements of meniscal volume, thickness, width, and bulging. Positional analyses included measurements of the overlap between the meniscal surface and tibial joint surface, the amount of extrusion, and the percentage of joint surface area and meniscal area that were covered or uncovered. Open MR scanners have been used to measure the movement of the menisci from full extension to deep flexion. MR compatible loading devices have been used to study the effect of loading on meniscal morphology and extrusion. Studies using these methods have found that there are differences in meniscal morphology between healthy and osteoarthritic participants, that the lateral meniscus and anterior horns have greater movement throughout flexion, and that meniscal extrusion increases under load. ConclusionsMRI has improved our insight into meniscal mechanics. Simulated weightbearing, open imaging through the range of knee flexion, and image processing to yield 3D measurements have all contributed to this progress. These approaches have strong potential to explore clinically motivated research questions related to meniscal mechanics.

DLL1/NOTCH1 signaling pathway maintain angiogenesis in meniscus development and degeneration

ObjectivesThe decline in vascular capacity within the meniscus is a well-documented phenomenon during both development and degeneration. Maintaining vascular integrity has been proposed as a potential therapeutic strategy for osteoarthritis. Therefore, our study aims to investigate the characteristics of endothelial cells and blood vessels in embryonic and degenerated meniscus tissues. MethodsHuman embryonic and mature menisci were used for histological analyses. Single-cell RNA sequencing was used to identify cell clusters and their significant genes in embryo meniscus to uncover characteristic of endothelial cells. Computer analysis and various staining techniques were used to characterize vessels in development and osteoarthritis meniscus. ResultsVessels structure first observed in E12w and increasing in E14w. Vessels were veins majorly and arteries growth in E35w. Endothelial cells located not only perivascular but also in the surface of meniscus. The expression of DLL1 was observed to be significantly altered in endothelial cells within the vascular network that failed to form. Meniscus tissues affected by osteoarthritis, characterized by diminished vascular capacity, displayed reduced levels of DLL1 expression. Experiment in vitro confirmed DLL1/NOTCH1 be vital to angiogenesis. ConclusionLack of DLL1/NOTCH1 signaling pathway was mechanism of vascular declination in development and degenerated meniscus.

Optimal standoff distance for a highly focused microjet penetrating a soft material

A needle-free injector using a highly focused microjet has the potential to minimize the invasiveness of drug delivery. In this study, the jet penetration depth in a soft material—which is a critical parameter for practical needle-free injections—was investigated. We conducted jet penetration experiments by varying the inner diameter of the injection tube and the standoff distance between the meniscus surface and the soft material. Interestingly, the results showed that the penetration depths peaked at certain distances from the meniscus, and the positions shifted further away as the inner diameter was increased. By analyzing the velocity distribution of the microjet, the peak positions of the penetration depth and the maximum velocities were inconsistent due to the effects of the jet shape. To account for this, we introduce the concept of the “jet pressure impulse,” a physical quantity that unifies the velocity and jet shape. However, direct estimation of this parameter from experimental data is challenging due to limitations in spatiotemporal resolution. Therefore, we used numerical simulations to replicate the experimental conditions and calculate the jet pressure impulse. Remarkably, the results show that the jet pressure impulse has peak values, which is consistent with the penetration depth. In addition, there is a correlation between the magnitude of the jet pressure impulse and the penetration depth, highlighting its importance as a key parameter. This study underlines the importance of the jet pressure impulse in controlling the penetration depth of a focused microjet, providing valuable insights for the practical use of needle-free injection techniques.

Spontaneous Recycling of Electrosprayed Sample by Retrograde Motion of Microdroplets.

Here, we discuss an interesting phenomenon occurring spontaneously near the sample liquid meniscus at the tip of the electrospray emitter. While most ejected droplets move from the emitter tip toward the counter electrode, some of the droplets decelerate and move backward to the liquid meniscus. When they hit the surface of the liquid meniscus, they either merge with the bulk liquid or get recharged during intermittent contact with the liquid meniscus and immediately reaccelerate toward the counter electrode. In some cases, while in contact with the meniscus they spontaneously form a secondary Taylor cone and emit progeny droplets. This observation suggests that the amount of electric charge transferred to such a droplet is sufficient to surpass the Rayleigh limit. Similar effects were previously observed for water as well as for NaCl-water and ethanol-water mixtures. However, here we observed it for electrolyte solutions commonly used in electrospray ionization mass spectrometry: methanol-water solutions with the addition of ammonium acetate, formic acid, or ammonium hydroxide. The reported phenomenon reveals the ongoing recycling of sample liquid in electrosprays. Such recycling can contribute to enhancement of sample utilization efficiency in electrospray ionization.

EXPERIMENTAL STUDY COMPARING THE DURATION OF PARTIAL MENISCUS RESECTION USING ARTHROSCOPIC PUNCHERS, RADIOFREQUENCY ABLATOR AND RADIOFREQUENCY INSTRUMENT FOR MENISCUS RESECTION "MENISCUS RESECTOR"

Introduction. An experimental study comparing the duration of partial resection of 500 mm3 of meniscus by a combination of arthroscopic punchers with a radiofrequency ablator and a radiofrequency resection tool "Meniscus Resector" was conducted in isolated laboratory conditions.
 The aim of the study. To determine and compare the duration of partial meniscus resection using arthroscopic punchers, radiofrequency ablator and Meniscus Resector radiofrequency resection tool in isolated laboratory conditions.
 Materials and methods. The study was conducted on 30 macropreparations of human knee menisci obtained during total knee arthroplasty, which were divided into two groups: Group 1 – 15 macroscopic specimens, partial resection of which was performed using an arthroscopic biter, and the contours of the meniscus surface after resection were treated with a radiofrequency ablator; Group 2 – 15 macroscopic specimens, partial resection of which was performed using the Meniscus Resector radiofrequency resection tool. In both groups, the same volume of meniscus was resected – 500 mm3. Visualization and timing were performed using an arthroscopic system (Smith & Nephew, USA; Loran, China). Statistical processing of the study data was performed using the licensed software IBM SPSS Statistics Base v 22. MedCalc (Healthcare Technology, USA).
 Results and Discussion. In group 1, the mean duration (median, interquartile range) of partial resection of a 500 mm3 fragment was 11.8 (10.2-12.9) seconds, in group 2, the mean duration of partial resection of a 500 mm3 fragment was 1.9 (1.4-2.3) seconds (p=0.000061). Thus, the use of the Meniscus Resector (group 2) contributed to an average of 6.2 times faster partial meniscus resection compared to arthroscopic punchers and radiofrequency ablator (group 1).
 Conclusions. The study suggests that the use of the Meniscus Resector provides a faster method of radiofrequency meniscus resection compared to arthroscopic punchers and radiofrequency ablators. Further studies and trials are needed to confirm these results and evaluate safety in different clinical settings.

Effects of Surface-Wave-Sustained Argon Plasma Torch Interaction with Liquids

In this paper, an investigation of the interaction of a surface-wave-sustained argon plasma torch with liquids is presented. The plasma is produced by an electromagnetic wave traveling along the plasma–dielectric interface, and at the same time, the plasma is a part of this waveguide structure. Because the interaction of the plasma torch with water (liquid) results in modifications of the properties of both the treated water and the plasma itself, a detailed study of the effects in both media is required. The results of the experimental investigation of a surface-wave-sustained argon plasma torch interaction with liquids show significant changes in the plasma parameters, such as the electron excitation temperature Te and the average rotation temperature Trot. In addition, mechanical waves are produced both in the meniscus surface and in the plasma torch by the interaction between the plasma torch (ionized gas with charged particles and electric field) and the liquid surface, which is different from the effects produced by a neutral gas jet on a liquid surface. As a result of the plasma–water interaction, the water’s chemical and physical characteristics, such as the water conductivity, pH, and H2O2 concentration, are modified. As a possible application for water purification, the performed SWD treatment of model wastewater shows a significant variation in nitrate, ammonium, phosphate, and COD (chemical oxygen demand) concentration as a result of the treatment.

Arthroscopic Suture-Saucerization of Discoid Meniscus Allows Volume Conservation but Does Not Fully Restore Coverage

The purpose of this study was to quantify the effect of meniscoplasty suture-saucerization on volume and surface coverage of lateral discoid menisci. This retrospective study included all consecutive 10 patients treated between 2014 and 2019 who had magnetic resonance imaging before and after surgery and 15 controls. The MITK 3M3 semiautomatic software was used to segment the meniscus and cartilage before and after surgery to measure the percentage of meniscus coverage on the tibial cartilage. Results are compared to control patients without knee pathology matched on sex and age with Student t test. Discoid meniscus surface and volume before surgery were respectively 597 mm2 (range, 550-887 mm2) and 2,822 mm³ (1,571-3,407 mm³), representing 74.5% (56%-89%) of the tibial cartilage surface. After surgery, it decreased to 422 mm2 (229-569 mm2) and 1,235 mm³ (680-1,738 mm³), leading to 45.7% (22.5%-68.6%) coverage. In the control group, median surface was 457 mm2 (314-641 mm2), volume was 1,321 mm3 (641-2,240 mm3), and tibial coverage was 55% (41%-77%). Altogether, meniscus volume after surgery was similar to normal, while coverage was significantly lower than controls (P= .04). Meniscoplasty suture-saucerization procedure may allow meniscus sparing and restauration of a similar to normal meniscus volume. Meniscus surface and coverage are diminished compared to controls. Both surface and volume normalization is usually not achievable without decreasing the thickness of the rather thick discoid meniscus. Both surface and volume normalization is usually not achievable without decreasing the thickness of thick discoid menisci.

Spin-up flow in ferrofluids: a toy model.

It is now more than 50 years since the first observation of ferrofluid spin-up by a rotating magnetic field by the author and R. Moskowitz. The ferrofluid rotated in direction opposite to that of the applied field. The intervening years have seen multiple unsuccessful attempts to explain this phenomenon. A clue was experimentally discovered by J. Popplewell and the author in 1987; rotation direction depends on shape of the ferrofluid meniscus. That notion is studied in further detail in the present work which describes tangential stress generated on the meniscus surface and an analytical expression for torque is developed. Increasing spin rate in smaller diameter vessels is rationalized. In addition, a physical picture of spin-up is introduced.

Geometry-Gradient Magnetocontrollable Lubricant-Infused Microwall Array for Passive/Active Hybrid Bidirectional Droplet Transport.

Manipulation of droplets has increasingly garnered global attention, owing to its multifarious potential applications, including microfluidics and medical diagnostic tests. To control the droplet motion, geometry-gradient-based passive transport has emerged as a well-established strategy, which induces a Laplace pressure difference based on the droplet radius differences in confined state and transport droplets with no consumption of external energy, whereas this transportation method has inevitably shown some critical limitations: unidirectionality, uncontrollability, short moving distance, and low velocity. Herein, a magnetocontrollable lubricant-infused microwall array (MLIMA) is designed as a key solution to this issue. In the absence of a magnetic field, droplets can spontaneously travel from the tip toward the root of the structure as a result of the geometry-gradient-induced Laplace pressure difference. When the subject of an external magnetic field, the microwalls bend and overlap sequentially, ultimately resulting in the formation of a continuous slippery meniscus surface. The formed meniscus surface can exert sufficient propulsive force to surmount the Laplace pressure difference of the droplet, thereby effectuating active transport. Through the continuous movement of the microwalls, droplets can be actively transported against the Laplace pressure difference from the root to the tip side of the MLIMA or continue to actively move to the root after finishing the passive self-transport. This work demonstrates passive/active hybrid bidirectional droplet transport capabilities, validates its feasibility in the accurate control of droplet manipulation, and exhibits great potential in chemical microreactions, bioassays, and the medical field.

Tensile energy dissipation and mechanical properties of the knee meniscus: relationship with fiber orientation, tissue layer, and water content.

Introduction: The knee meniscus distributes and dampens mechanical loads. It is composed of water (∼70%) and a porous fibrous matrix (∼30%) with a central core that is reinforced by circumferential collagen fibers enclosed by mesh-like superficial tibial and femoral layers. Daily loading activities produce mechanical tensile loads which are transferred through and dissipated by the meniscus. Therefore, the objective of this study was to measure how tensile mechanical properties and extent of energy dissipation vary by tension direction, meniscal layer, and water content. Methods: The central regions of porcine meniscal pairs (n = 8) were cut into tensile samples (4.7mm length, 2.1mm width, and 0.356mm thickness) from core, femoral and tibial components. Core samples were prepared parallel (circumferential) and perpendicular (radial) to the fibers. Tensile testing consisted of frequency sweeps (0.01-1Hz) followed by quasi-static loading to failure. Dynamic testing yielded energy dissipation (ED), complex modulus (E*), and phase shift (δ) while quasi-static tests yielded Young's Modulus (E), ultimate tensile strength (UTS), and strain at UTS (εUTS). To investigate how ED is influenced by the specific mechanical parameters, linear regressions were performed. Correlations between sample water content (φw) and mechanical properties were investigated. A total of 64 samples were evaluated. Results: Dynamic tests showed that increasing loading frequency significantly reduced ED (p < 0.05). Circumferential samples had higher ED, E*, E, and UTS than radial ones (p < 0.001). Stiffness was highly correlated with ED (R2 > 0.75, p < 0.01). No differences were found between superficial and circumferential core layers. ED, E*, E, and UTS trended negatively with φw (p < 0.05). Discussion: Energy dissipation, stiffness, and strength are highly dependent on loading direction. A significant amount of energy dissipation may be associated with time-dependent reorganization of matrix fibers. This is the first study to analyze the tensile dynamic properties and energy dissipation of the meniscus surface layers. Results provide new insights on the mechanics and function of meniscal tissue.

Visualizing experimental investigation on gas–liquid replacements in a microcleat model using the reconstruction method

AbstractCleats are the main channels for fluid transport in coal reservoirs. However, the microscale flow characteristics of both gas and water phases in primary cleats have not been fully studied as yet. Accordingly, the local morphological features of the cleat were determined using image processing technology and a transparent cleat structure model was constructed by microfluidic lithography using the multiphase fluid visualization test system. Besides, the effect of microchannel tortuosity characteristics on two‐phase flow was analyzed in this study. The results are as follows: (1) The local width of the original cleat structure of coal was strongly nonhomogeneous. The cleats showed contraction and expansion in the horizontal direction and undulating characteristics in the vertical direction. (2) The transient flow velocity fluctuated due to the structural characteristics of the primary cleat. The water‐driven gas interface showed concave and convex instability during flow, whereas the gas‐driven water interface presented a relatively stable concave surface. (3) The meniscus advanced in a symmetrical pattern in the flat channel, and the flow stagnated due to the influence of undulation points in a partially curved channel. The flow would continue only when the meniscus surface bypassed the stagnation point and reached a new equilibrium position. (4) Enhanced shearing at the gas–liquid interface increased the gas‐injection pressure, which in turn increased residual liquids in wall grooves and liquid films on the wall surface.

Advanced bioactive glue tethering Lubricin/PRG4 to promote integrated healing of avascular meniscus tears

Meniscus injuries are extremely common with approximately one million patients undergoing surgical treatment annually in the U.S. alone, but no regenerative therapy exist. Previously, we showed that controlled applications of connective tissue growth factor (CTGF) and transforming growth factor beta 3 (TGFβ3) via fibrin-based bio-glue facilitate meniscus healing by inducing recruitment and stepwise differentiation of synovial mesenchymal stem/progenitor cells. Here, we first explored the potential of genipin, a natural crosslinker, to enhance fibrin-based glue's mechanical and degradation properties. In parallel, we identified the harmful effects of lubricin on meniscus healing and investigated the mechanism of lubricin deposition on the injured meniscus surface. We found that the pre-deposition of hyaluronic acid (HA) on the torn meniscus surface mediates lubricin deposition. Then we implemented chemical modifications with heparin conjugation and CD44 on our bioactive glue to achieve strong initial bonding and integration of lubricin pre-coated meniscal tissues. Our data suggested that heparin conjugation significantly enhances lubricin-coated meniscal tissues. Similarly, CD44, exhibiting a strong binding affinity to lubricin and hyaluronic acid (HA), further improved the integrated healing of HA/lubricin pre-coated meniscus injuries. These findings may represent an important foundation for developing a translational bio-active glue guiding the regenerative healing of meniscus injuries.

Medial Meniscal Posterior Root Avulsion Fracture Repair Using the Nice Knot

Meniscal root tears have recently seen an increase in diagnosis. As we understand more about the biomechanical relationship between the meniscus and tibiofemoral articular surface, it becomes more important to promptly identify and repair these lesions. Root tears may cause up to a 25% increase in forces in the tibiofemoral compartment, potentially leading to hastened degenerative changes visible on radiographs and decreased patient outcomes. The anatomic footprint of the meniscal roots has been described, as well as multiple iterations of repair techniques, with the most popular being the arthroscopic-assisted transtibial pullout technique for repair of the posterior meniscal roots. The tensioning technique varies and has been a surgical step that can lead to error during the procedure. We use a transtibial technique with modifications in the method of suture fixation and tensioning. To begin, we use 2 doubled-over sutures that are passed through the root to create a looped end and a twin-tailed end. This is followed by the use of a locking, tensionable and, if needed, reversible Nice knot that is tied on the anterior tibial cortex over a button. This technique provides controlled and accurate tension to the root repair when tied over a suture button on the anterior tibia with stable suture fixation to root.

ДИНАМИКА И КИНЕМАТИКА ДВИЖЕНИЯ МЕНИСКА ЖИДКОСТИ В КАПИЛЛЯРЕ

The role of capillary pressure as a factor determining the dynamics and kinematics of the capillary flow is considered. The observed axial flow is considered as a consequence of the radial flow of the fluid bordering the surface of the meniscus. It is shown that the radial flow is due to the gradient of the superficial tension of the meniscus caused by the deformation of the meniscus surface by the forces of fluid adhesion to the capillary wall. An estimate of current velocities is given. Under typical conditions, the velocity of the radial flow is by a factor of ten greater than the flow velocity along the capillary axis when the volume velocities calculated from the values of the tension gradient and the capillary pressure, respectively, are equal. It is concluded that the observed movement of the meniscus is caused by the flow of fluid on the surface of the capillary, in which the axial component of the flow rate on the capillary wall is zero. This eliminates the contradiction between the apparent movement of the meniscus and the equation of the axial flow of fluid in the capillary, according to which the speed on the wall should be zero

Comparison of adhesion of thawed and cultured synovial mesenchymal stem cells to the porcine meniscus and the relevance of cell surface microspikes

BackgroundPlacement of a cultured synovial mesenchymal stem cell (MSC) suspension on a repaired meniscus for 10 min accelerated meniscus repair. Upon placement of the MSC suspension on the meniscus, microspikes projecting from the MSC surface trap meniscus fibers and promote MSC adhesion. Thawed cryopreserved MSCs are preferred materials for meniscus repair, as they can be transplanted without additional culture. However, the adhesion ability of thawed cryopreserved MSCs is unknown. Here, we compared the proportion of cultured versus thawed MSCs adhering to a porcine meniscus immediately and 10 min after placement. We also investigated the relationship between adhesion and the number of microspikes on the synovial MSCs.MethodsSynovial MSCs were prepared from the knees of four donors with osteoarthritis. The “cultured MSCs” were thawed MSCs that were re-cultured and suspended in PBS for transplantation. A similarly prepared suspension was cryopreserved, thawed again, suspended in PBS, and used without further culture as the “thawed MSCs.” MSCs with at least three microspikes in SEM images were defined as microspike-positive MSCs. Porcine meniscus surfaces were abraded, cut into a cylindrical shape, and treated with MSC suspension. Non-adherent cells were counted immediately and again 10 min after placement to calculate the adhesion proportion.ResultsThe proportion of microspike-positive MSCs was significantly higher in thawed (53 ± 3%) than in cultured (28 ± 5%) MSC suspensions. MSC adhesion to the meniscus was significantly better for the thawed than for the cultured MSC suspensions immediately after placement on the meniscus, but no differences were detected after 10 min. The proportion of MSCs with microspikes in the cell suspension was significantly correlated with the proportion of adhered MSCs immediately after the placement, but not 10 min later. Addition of FBS to the cryopreservation medium promoted a concentration-dependent increase in the proportion of microspike-positive cells.ConclusionsThawed MSCs adhered better than cultured MSCs immediately after placement, but adhesion was similar for both MSC preparations after 10 min. Immediately after placement, the presence of microspikes was associated with better adhesion of synovial MSCs to the meniscus.

Evaluation of Health Care Disparities in Patients With Anterior Cruciate Ligament Injury: Does Race and Insurance Matter?

Background:It is unknown whether race- or insurance-based disparities in health care exist regarding baseline knee pain, knee function, complete meniscal tear, or articular cartilage damage in patients who undergo anterior cruciate ligament reconstruction (ACLR).Hypothesis:Black patients and patients with Medicaid evaluated for ACLR would have worse baseline knee pain, worse knee function, and greater odds of having a complete meniscal tear.Study Design:Cross-sectional study; Level of evidence, 3.Methods:A cohort of patients (N = 1463; 81% White, 14% Black, 5% Other race; median age, 22 years) who underwent ACLR between February 2015 and December 2018 was selected from an institutional database. Patients who underwent concomitant procedures and patients of undisclosed race or self-pay status were excluded. The associations of race with preoperative Knee injury and Osteoarthritis Outcome Score (KOOS) Pain subscale, KOOS Function subscale, and intraoperatively assessed complete meniscal tear (tear that extended through both the superior and the inferior meniscal surfaces) were determined via multivariate modeling with adjustment for age, sex, insurance status, years of education, smoking status, body mass index (BMI), meniscal tear location, and Veterans RAND 12-Item Health Survey Mental Component Score (VR-12 MCS).Results:The 3 factors most strongly associated with worse KOOS Pain and KOOS Function were lower VR-12 MCS score, increased BMI, and increased age. Except for age, the other two factors had an unequal distribution between Black and White patients. Univariate analysis demonstrated equal baseline median KOOS Pain scores (Black, 72.2; White, 72.2) and KOOS Function scores (Black, 68.2; White, 68.2). After adjusting for confounding variables, there was no significant difference between Black and White patients in KOOS Pain, KOOS Function, or complete meniscal tears. Insurance status was not a significant predictor of KOOS Pain, KOOS Function, or complete meniscal tear.Conclusion:There were clinically significant differences between Black and White patients evaluated for ACLR. After accounting for confounding factors, no difference was observed between Black and White patients in knee pain, knee function, or complete meniscal tear. Insurance was not a clinically significant predictor of knee pain, knee function, or complete meniscal tear.

Meniscus surface texture is associated with degenerative changes in biological and biomechanical properties

Meniscal degeneration is defined by semi-quantitative assessment of multiple histological findings and has been implicated in biomechanical dysfunction, yet little is known about its relationship with biological properties. This paper aimed to quantitatively evaluate degenerative findings in human meniscus to examine their relationship with gene expression and biomechanical properties, and to extract histological findings that reflect biological properties like gene expression and cytokine secretion. This study included lateral menisci of 29 patients who underwent total knee arthroplasty. The menisci were divided into six samples. For each sample, Pauli's histological evaluation and corresponding quantitative assessment (surface roughness, DNA content, collagen orientation, and GAG content) were performed, with surface roughness showing the highest correlation with the histological evaluation in a single correlation analysis (r = 0.66, p < 0.0001) and multivariate analysis (p < 0.0001). Furthermore, surface roughness was associated with gene expression related to meniscal degeneration and with tangent modulus which decreases with increasing degeneration (r = − 0.49, p = 0.0002). When meniscal tissue was classified by surface integrity, inflammatory cytokine secretion tended to be higher in severe degenerated menisci. These results suggest that the evaluation of meniscal surface texture could predict the degree of degeneration and inflammatory cytokine secretion.

Total knee replacement for ochronotic arthritis: A rare case report

Introduction and importanceTotal knee replacement (TKR) is commonly performed for managing advanced osteoarthritis. There are several causative factors of osteoarthritis, from degenerative processes associated with age to rare genetic disorders correlated with a rare course of disease and remained undetected even until adulthood. Herein, we present a case of ochronotic arthritis characterized by black discoloration of the articular cartilage, meniscus, and soft tissue surrounding the right knee, which was detected during TKR, in a patient with alkaptonuria. This is a rare case and managing the patient require conscientious approach.Case presentationFor the past four years, a 64-year-old man had been experiencing chronic right knee pain. During admission, the patient was limping and unable to bear weight on the affected knee. The right knee was swollen, with limited range of motion and audible crepitation during flexion. Radiography revealed narrowing of the joint space and osteophytes on the articular surface. Further investigation showed that the patient was previously diagnosed with alkaptonuria and was scheduled for TKR. Intraoperatively, we found that the articular cartilage, meniscal surface, and soft tissue surrounding the knee had black discoloration. Thus, additional debridement of soft tissues was required.Clinical discussionAlkaptonuria may increase the risk of osteoarthritis in the knee joint. Ochronosis correlated with alkaptonuria. Diagnosis can be conducted with physical examination, synovial fluid exam and complete urinalysis to avoid misdiagnose of this disease.ConclusionIn our study, TKR for ochronotic arthritis had good outcomes, with a knee score of 95 and a function score of 90. The patient received routine treatment for alkaptonuria at the Urology Department.